This invention relates to a diagnostic test drug comprising monoclonal antibody to human copper.zinc-superoxide dismutase and a diagnostic test method using the same, and more specifically to a diagnostic test drug comprising monoclonal antibody to human copper.zinc-superoxide dismutase which is capable of conducting diagnosis of various diseases with good precision and good reproducibility and a diagnostic test method using the same.
Superoxide dismutase (SOD) is an enzyme distributed very widely in biological world and catalyzes the reaction as shown below which disproportionates the superoxide anion radicals (O.sub.2.sup.-) which are principal molecular species of toxic oxygen: EQU O.sub.2.sup.- +O.sub.2.sup.- +2H.sup.+ .fwdarw.H.sub.2 O.sub.2 +O.sub.2
SOD is classified into the three kinds of Cu.Zn--SOD (a dimer having a molecular weight of about 32,000), Mn--SOD and Fe--SOD (both are dimers having a molecular weight of about 40,000). In the respective human tissues, Cu.Zn--SOD is confirmed in the cytoplasm portion and Mn--SOD in the matrix portion of mitochondrion.
For Fe--SOD and Mn--SOD, high homology can be seen in their amino acid sequences between biological species and evolutional analogical relationship is estimated therebetween. In contrast, Cu.Zn--SOD is inherent in eucaryote and has a different amino acid sequence from other kinds of SOD. The Cu.Zn--SOD has been clinically recognized to have anti-inflammatory action, and the Cu.Zn--SOD derived from bovine is now under progress of development as therapeutical agent for inflammatory diseases such as chronic rheumatism. However, as a pharmaceutical, the Cu.Zn--SOD derived from human is considered to be more excellent than that derived from bovine in aspect of antigenicity. Accordingly, when an anti-human Cu.Zn--SOD antibody having very high specificity is used for purification of Cu.Zn--SOD contained in human organs (e.g. placenta) or human Cu.Zn--SOD produced in microorganism by genetic manipulation, the purification step can be by far easier than the conventional method and further still higher purity can be obtained.
On the other hand, Sawaki, Sugiura et al examined about the relationship between measured values of human serum SOD and various diseases with the use of antiserum to human SOD obtained from rabbit (reported in the 55th general meeting of Biochemical Society of Japan). According to their experimental results, the Cu.Zn--SOD value in human serum becomes some 10-fold in kidney failure, particularly uremia, and is increased to several fold in hepatitis, diabetes accompanied with complications, fibroid lung, etc. The above facts indicate that Cu.Zn--SOD can be a marker for diagnosis of these diseases.
The present inventors have studied intensively in order to develop a method for conducting diagnosis of the above various diseases with good precision and good reproducibility, and consequently found that the method in which an amount of Cu.Zn--SOD in human serum can be detected with good precision by use of monoclonal antibody specific for the human Cu.Zn--SOD can be effected for diagnosis of the cancer of the stomach to accomplish the present invention.